const fp = require('lodash/fp')

const cars = [
    {
        name: 'F FF',
        horsepower: 660,
        dollar_value: 70000,
        in_stock: true,
    },
    {
        name: 'A C12 z',
        horsepower: 650,
        dollar_value: 648000,
        in_stock: true,
    },
    {
        name: 'J KKR',
        horsepower: 550,
        dollar_value: 132000,
        in_stock: false,
    },
    {
        name: 'Audi R8',
        horsepower: 525,
        dollar_value: 144200,
        in_stock: false,
    },
    {
        name: 'AMO',
        horsepower: 750,
        dollar_value: 1850000,
        in_stock: true,
    },
    {
        name: 'PH',
        horsepower: 700,
        dollar_value: 1300000,
        in_stock: false,
    },
]

// 练习一
let isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last)
console.log(isLastInStock(cars))

// 练习2
let firstName = fp.flowRight(fp.prop('name'), fp.first)
console.log(firstName(cars))

// 练习3
let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length
}

let averageDollarValue = fp.flowRight(_average, fp.map(fp.prop('dollar_value')))
console.log(averageDollarValue(cars))

// 练习4
let _underscore = fp.replace(/\W+/g, '_')

let sanitizeNames = fp.map(fp.flowRight(_underscore, fp.lowerCase))
console.log(sanitizeNames(['Hello World']))
